Frequency determining unit



May 7, 1946. K. K GARRISON FRE IQUENCY DETERMINING UNIT Filed Aug. 4, 1944 mmm x' Patented May 7, 1946 FREQUENCY DETERMINING UNIT Kenton Kitch Garrison. East Orange, N. 1., assignor to Federal Telephone and Radio Corporation, New York, N. Y.. a corporation of Delaware I Application August 4, 1944, Serial No. 548,109

'1 Claims.

The present invention relates to resonator unit assemblies for crystal controlled oscillator circuits and consists of an improved housing and supporting arrangement for a piezo-electric crystal element of simplified and advantageous construction. Important objects accomplished by the improvements are to produce a structure designed for improved ease and economy of manufacture, compactness, with' maximum protection of the crystal and mounting parts from atmospheric or other disturbances and security against displacement of the crystal element. It further incorporates an advanced type of resilient contact mounting of the crystal designed to materially reduce undesired mechanical damping of the crystal vibrations by a mounting support providing maximum freedom of crystal movement.

The foregoing and other features and advantages of the present invention will be more fully understood by reference to the accompanying drawing wherein like reference characters are applied to the corresponding parts in the several views.

In the drawing,

Fig. l is a view, the major portion of which is a central, vertical section of an assembled resonator unit constructed to embody the features of the invention;

Fig. 2 is a central vertical sectional view taken at right angles thereto:

Fig. 3 is a cross sectional view taken on line 3-3 of Fig. 1;

Fig. 4 is a bottom plan view of thecover memher, and

Fig. 5 is a view generally similar to Fig. 1 and illustrating a modified construction.

Fig. 6 is a partial sectional view of a modified crystal and electrode structure.

In its preferred structural embodiment as here shown, the features of the invention are incorporated in a resonator unit of the end loading and of the top loading type as shown in Figs. 1 to 4. The unit assembly is of the plug-in pin terminal construction comprising a body or housing I provided with an internal, bottom opening socket 2 for the reception of the resonator element or crystal 3 and the cooperating contacts for making electrical connection with the electrodes thereof. The resonator electrodes 4 in the customary manner are provided by applying a silver coating to the opposite faces of the crystal as indicated. The contacts 5-! for engaging the electrodes are of resilient or flat spring metal tion 1.

ing to the spaced terminal or plug-in pins 6 secured by being molded in the plastic insulatin material of the housing lower wall or base por- In further accordance with the invention the crystal element is shown vas of a special and improved formation having its opposite upper and lower ends of tapered or blunt chisel formation and the resilient contacts and likewise the cover member 8 are of special formation for cooperating with the crystal for supporting it with a minimum damping of its natural vibration.

For this purpose the contact members are formed to be upwardly and'inwardly extending and have outwardly flared or curved extremities 9 thereby providing a contact support for the lower end of the crystal of opposite contact members in truncated conical formation adapted to receive the end of the crystal with resilient out-' ward deflection of its opposite members. In addition thereto one of its contact members, the left hand member, as illustrated. is formed with an integral horizontally turned supporting lip or shoulder in providing an integral stop and support for the crystal element to limit its insertion and to reduce scratching and marking of the electrode surfaces. termines the vertical position of the crystal element which as disclosed has a vertical dimension or length so as to extend Slightly above the 9 upper horizontal surface or plane or the housing member 5 so as to be received within a transverse groove Ii formed in the underside of the cover member 3 and having inclined side walls or surfaces slightly less acute than that of the beveling of the crystal end. The engagement of the crystal within the cover groove as thus provided determines the proper position of the crystal. As will be further readily appreciated this supporting arrangement greatly facilitates the assembling which is accomplished by the mere insertion of the crystal between the fiared ends of the contacts and in engagement with the lip l0 after which the projecting upper end of the crystal end is readily engaged or received within the cover groove to effect proper positioning upon securing of the cover to the housing member. The latter is accomplished in the usual manner by the employment of securing screws I! passed through apertures in the cover and threaded into the housing with the usual resilient washer ele- This supporting lip de ment is interposed between the cover lower and housing upper end surfaces. The electrode coatings as shown. may desirably be extended the full length of the crystal and slightly over the beveled portions of its ends but with suitable spacing from the apex of the bevels to insure proper electrical separation.

The simplified and improved design and structural arrangement provides for effective cooperation with the special crystal formation to eifect good electrical contact with the electrodes at one and provided with electrodes on its opposite faces; said container comprising separable base and cover members, one of said members being provided with resilient contact elements formed with opposed flared end portions for electrical connection with the electrodes at one end of the crystal and, one of said contacts being provided with a supporting lip to be engaged by an end of the a crystal and said other supporting member being end thereof only and in a-manner of contact engagement to produce a materially reduced compressive force on the crystal in the direction longitudinally thereof. The contact and securing engagement with the crystal as thus ailorded, in addition to reducing the axial pressure on the crystal, further provides (or electrical contact with the electrodes in a desirable manner inwardly of the outer plane of vibration of the crystal whereby the engagement is inward toward the axis and thereby effects electrical contact with a minimum of restrictive influence upon the natural vibration of the resonator element. Moreover by reason of the resilient support offered by the lip portion i0, determining the position of the crystal, provision is made for a desirable range of self adjustment to accommodate for variations in production tolerances.

Aswill be readily understood, varied modifications may be made in the structure without departing from the scope of the invention as defined in the appended claims. As illustrative thereof, there is shown in Fig. 5 a modification wherein the container provided is separable at the base portion and wherein the base member indicated at I is provided with the terminal pins l5 molded therewith and having connected thereto in similar manner the contacts I6 corresponding in form and arrangement to that first described. In this instance the cover member I! is the housing element and is formed with the internal' socket it having the cooperative supporting groove is formed in its innermost wall. The separable container members of insulating material are secured by securing screws passed through the base portion and threaded to the cover or housing.

In Fig. 6 there is shown a modified structure of the crystal element wherein there is applied over the usual silver plating electrode a supplemental nickel plated layer 20 overlying the silver at the contact area or end portion 01 the crystal. This will withstand greater wear as will be understood.

What is claimed is:

1. A frequency determining unit of the character descrribed comprising a container providing a socket for the reception of a resonator element, 9. crystal element positioned in the socket and provided with electrodes on its opposite sides, said container comprising separable base and cover members, one of said members being provided with combined resilient supporting and contact elements for effecting electrical connection with the electrodes at one end of the crystal and said other member being formed with a positioning groove for cooperating supporting engagement with the opposite end of the crystal element.

2. A frequency determining unit of the character described comprising a container providing a socket for the reception of a resonant element, a crystal element positioned in the socket formed with a positioning groove for cooperative supporting engagement with the opposite end of the crystal element.

3. A frequency determining unit of the character described comprising a container providing a socket for the reception of a resonant element, 9. crystal element positioned in the socket and provided with electrodes on its opposite faces; said container comprising separable base and cover members, the base members being provided with resilient contact elements formed with opposed fiared end portions for electrical connection with the electrodes at one end of the crystal and one of said contacts being provided with a horizontal supporting lip to be engaged by an end of the crystal, said cover memberv being formed with a positioning groove for cooperative supporting engagement with the opposite end of the crystal element and means for securing the base and cover members together.

4. A frequency determining unit of the character described comprising a container providing a socket for the reception of a resonant element, a crystal element positioned in the socket and provided with electrodes on its opposite faces; said container comprising separable base and cover members, the base member being formed with a socket and provided with resilient contact elements formed with oppositely inclined portions having opposed flared ends for electrical connection with the electrodes at one end of the crystal, one of said contacts being provided with a supporting lip to be engaged by an end of the crystal and said cover member being formed with a positioning groove for cooperative supporting engagement with the opposite end of the crystal element, said crystal being formed with beveled ends.

5. A frequency determining unit of the character described comprising a container providing a socket for the reception of a resonant element, a crystal element positioned in the socket and provided with electrodes on its opposite faces; said container comprising separable base and cover members, the base member being formed with a socket,and provided with resilient contact elements formed with oppositely inclined portions having opposed fiared ends for electrical connection with the electrodes at one end of the crystal, one of said contacts being provided with a supporting lip to be engaged by an end of the crystal and said cover member being formed with a positioning groove for cooperative supporting engagement with the opposite end of the crystal element, said crystal being formed with beveled ends and having a length to extend slightly above the base upper end to enter the cover groove.

6. A frequency determining unit of the character described comprising a container providing a socket for the reception of a resonant element, a crystal element positioned in the socket and provided with electrodes on its opposite faces: said container comprising, separable base and cover members, the base member being provided with resilient contact elements formed with oppositively inclined positions having opposed flared ends for electrical connection with the electrodes at one end 01 the crystal. one of said contacts being provided with a supporting lip to be engaged by an end or the crystal andsaid cover member being formed with a positioning groove for cooperative supporting engagement with the opposite end of the crystal element, said crystal being formed with beveled ends and having a length to extend slightly above the base upper end to enter the cover groove.

7. A piezo-electric crystal element comprising a crystal 0! plate formation having electrode plat- 5 ing on its opposite faces and a supplemental plating of nickel overlying the electrode plating at the area oi contact engagement.

KENTON' KI'I'CH GARRISON. 

